Monday, April 18, 2011

We get kind of crazy around here at the end of a long, hard winter! But, here's the thing-folks are always asking us how they can make their own rennet. I don't know why. Maybe it's because so many home cheese makers are dyed-in-the-wool do-it-yourselfers.

So, I was going to do a post about that subject, but I soon realized that there are so many ways to make rennet that I would have to write at least 5 articles (which I will probably eventually do!)

In the cheese forums, folks frequently ask about using fig juice. I initially thought that if I did an article about that, it would only be useful to folks in Mediterranean countries. But I discovered that the US, Turkey, Greece and Spain are the main producers of dried figs. Within the US, figs are commercially grown in California, Texas, Utah, Oregon and Washington. (valleyfig.com)

So, I started my research and I found out there really isn't much information online about using fig juice to coagulate milk. In fact, pretty much everything I could find is in this article!

What is fig juice?

Fig juice/sap/latex is the milky stuff that comes off a fig tree branch in much the same way that sap comes off a maple tree. However, before you go running out to your backyard, heed this warning- it can be very toxic to folks who are sensitive to it, resulting in a terrible rash. So, be safe and wear gloves. (On the other hand, if you have a wart, you could try placing one drop of fig latex on it because supposedly that will make it disappear!)

Apparently, this is powerful stuff. In the 1988 Second Kenya National Seminar on Agroforestry, there is mention of fig juice:

Ficus latex contains a natural proteolytic enzyme, ficin, which in combination with other enzymes present, can be used to coagulate the protein in milk, similar to rennet for the preparation of cheeses and junkets, and in medicines.The clotting activity of fresh fig latex from F. carica is 30-100 times that of animal rennet.

When and where was it used as rennet?

The ancient Romans knew about it:

Soldiers would have known they could use the juice of the fig tree as a rennet from the Iliad. For example, Homer writes in book five when Ares has been speared and blood flows from his wound:

"even as the juice of the fig speedily maketh to grow the white milk that is liquid but is quickly curdled as a man stirreth it, even so swiftly healed the furious Ares." (romanarmy.net)

16th century Italians appear to have used it in addition to their calf rennet:

One takes six parts of this rennet (veal) and two of strong acid and one of milk from fig leaves and one mixes it well together, and this mixture has a miraculous effect, it makes that the cheese made with this rennet never spoils; because the milk of the fig and the vinegar conserves it from every putrefaction; it is like aqua vita what keeps wine and doesn't let it become corrupt, and these are the ultimate and grand secrets of nature; and if one well attends to matters of little importance nevertheless in these one finds the high and great rational secrets. (From a translation of 16th Century Italian Cheese Recipes at florilegium.org)

Relatively recently, there seems to be renewed interest in it:

One study (2002) by the Food Engineering Dept. at Gaziantep University in Turkey compares cheese made with calf rennet to cheese made with fig juice:

The results of triangle tests indicated that the difference between Gaziantep cheese made with rennet and enzyme preparation obtained from ion-exchange chromatography, was not significant (P < 0.05). Organoleptic tests showed that there was no significant difference in acidity, bitterness, creaminess, off-flavour and graininess with the LSD method (P < 0.05).It was concluded that fig tree latex is suitable as a chymosin substitute, and could be used in Gaziantep cheese production.

Another 2010 study in the International Journal of Food Properties was done with ewe's milk and the results were similar:

... Plant coagulant induced shorter gelation time compared to chymosin however required longer time for restructuration (end of coagulation).The coagulum obtained with the latex of Ficus carica (fig juice) had a higher yield, owing to its high water retention capacity. With the exception of color, the overall sensory attributes did not show significant differences among coagulants.(informaworld.com)

Substitutes were sought from plants, including ficin from the fig tree, papain from the papaya tree, and bromelin from pineapple. The resulting cheeses were extremely bitter due to the excessive proteolytic activities of the enzymes. In addition, considerable activity was retained after heating to 80C, and all required a higher milk setting temperature in the vat.

How is it used?

There are many different ways to extract and use the fig latex:

The ancient sources, in this case Aristotle, even tell us the way fig juice, in ancient Greek opos, was harvested:

"The juices flowing from an incision in green bark is caught on some wool. The wool is then washed and rinsed into a little milk, and if this be mixed with other milk it curdles it."(romanarmy.net)

Sikma cheese is mainly produced from sheep milk using rennet within 1-2 hr. Fig juice had been used previously for curd formation for sikma cheese.Fig juice was dried on a cloth and stored, when required it was dissolved in warm milk and then used in cheese production.This method has been completely abandoned now.

The Center for New Crops & Plant Products, at Purdue University mentions this in their fig section:

Latex: The latex contains caoutchouc (2.4%), resin, albumin, cerin, sugar and malic acid, rennin, proteolytic enzymes, diastase, esterase, lipase, catalase, and peroxidase.It is collected at its peak of activity in early morning, dried and powdered for use in coagulating milk to make cheese and junket. From it can be isolated the protein-digesting enzyme ficin which is used for tenderizing meat, rendering fat, and clarifying beverages.

In a lighter vein, here's an entry from 2010 in the Cheese Forum, in answer to the question of whether fig juice can be used as rennet:

Yes, you need to collect the sap and use that. It's a milky white sort of liquid. A good way is to cut some twigs, make lateral cuts to pierce the outer layers, and soak in water. You don't need to use very much - ficin in a strong enzyme.Something like 4-5 drops of the pure sap will set up a gallon of milk. It's easier to use leaves if you have them. You can cut the large leaves and drip the sap into a catch vessel.

For preparing the rennet, the latex is collected in the early morning hours when both the yield and the enzyme activity are high. A solid preparation may be obtained from the latex (which contain rennin, proteolytic enzymes, diastase, esterase, lipase, catalase and peroxidase apart from sugar, malic acid etc.) by direct drying in vacuum where a white solid is obtained. One c.c. of the latex yields 0.10 to 0.15 g of the dry powder which retains 90-95% of the activity originally present in the latex for several months at room temperature, more if ascorbic acid is added.

I'm very interested in this, but concerned... are there any adverse health effects that could come from ingesting fig sap in cheese? We just purchased several young fig trees yesterday and this would be such a cool way to make out goat cheese without commercial rennet!

Tanglewood,Everything I know about this is in the article. There isn't much more info available online. That said, it does appear that folks have been making cheese with it for thousands of years, so...JeriPS If you try it, let me know!

Thank you so much for your so useful article! It's a big and hard job!I was searching after same recipe for veg. rennet during last couple of days.But I understand that alternative source of rennet without bitterness - is dryed flowers of cardoonHerehttp://www.artisancheesemakingathome.com/creatingcheese-morecheeses.htmlyou can find address of that sell this dry flowers.

We did it! We boiled 2/3 cup milk and after taking it off the heat, stirred it with a freshly broken off fig stick. After about 1 minute the milk began to curdle and soon clearly separated into curds and whey. One of us thought it was a tiny bit bitter, the other didn't notice any bitterness at all. All this was done in the morning--I don't know how well the sap flows at other hours.

Check out this web site for more about making cheese using fig sap: http://blog.pjvoice.com/diary/503/home-made-goat-cheese-for-shavuot

The fig tree in the next-to-last photo is not the fig tree (ficus carica) you and the ancients are talking about. it is a tropical strangler fig or banyan (probably ficus macrophylla or ficus aurea). You might want to replace it with an accurate representation of the correct fig tree.

I think it will be very interstitng to try cardoon thistles too ( I found this information in the site of Mary Karlin and from Italian cheese makers), but i still wasn't found dry cardoon thistles on my region ( it's too much expensive to order from US). There are traditional Tunisian drink Raib that made cardoon-clotted milk.

I may do another article about making rennet at some point, and I will check out cardoon thistles. Meanwhile, Raib sounds interesting. If you have a recipe for it, I would like to do an article about it- jeri1000@gmail.com.

Just to add some more to there's another plant that is good to make rennet and i coan found all over in the wild in my country Portugal , Thistle Flower - Flor do Cardo (family Asteraceae), and is the common rennet to most part of the cheese making http://en.wikipedia.org/wiki/Thistle , http://en.wikipedia.org/wiki/Serra_da_Estrela_cheese DOP enjoy :D

A far as using cardoon thistle, as well as wild thistle, I just bumped into a paper at http://eithni.com/ReferenceDesk/RomanCheese.pdf all about cheese technology in ancient Rome. It specifically mentions using the flower of the wild thistle and the blessed thistle. So it sounds like any thistle you happen to have handy might work.

Excellent article... thanks for sharing! I read that the plant traditionally used in Spain and other Mediterranean countries to make cheese was cynara cardunculus, a wild cardoon, or cynara humilis,, a wild thistle. There are some cheeses sold in Spain nowadays that require this specific kind of rennet, so it is sure that it works well; but it seems to be a bit more difficult to use than the traditional one. Thanks again for your article.